Due to the characteristics of high brightness, low power consumption and so on, light emitting diode (LED) has rapidly replaced the conventional light sources for illumination in many applications, like display. The light source used for illumination requires high brightness of white light. Therefore, the whole industry now focuses on the research and development of white light LED.
At present, white light LED having high brightness can be obtained by using phosphor powder with blue light chip (such as GaN). The blue light emitted from the chip may excite the phosphor powder to generate another wavelength of light (such as yellow light). By mixing the blue light and the yellow light, an expected white light is obtained. As to the LED packaging, dispensing or surface coating is usually utilized.
The advantage of utilizing dispensing or surface coating to package LED is simple in process. However, the problem of uneven color of light may easily occur in the dispensing process because the quantity of glue can not be easily controlled.
Please refer to FIG. 1, as an example to show the problems of light emitting diode packaging structure in the prior art. In FIG. 1, the conventional light emitting diode packaging structure 10 includes a base 11 on which a pad 13 is provided; a substrate 15; a semiconductor layer 17; an electrode 18; a conducting wire 20 connecting the electrode 18 to the pad 13 on the base 11; and a phosphor encapsulant 22 having phosphor powder for sealing the pad 13, the substrate 15, the semiconductor layer 17, the electrode 18, and the conducting wire 20 on the base 11.
The phosphor encapsulant 22 having a phosphor powder will be formed as a hemisphere shape during a dispensing process. Therefore, the light emitted from the LED may be changed according to the various thickness of the phosphor encapsulant even if the phosphor powder is evenly dispersed within the encapsulanting gel 22, because the light emitted from different regions of the semiconductor layer may pass through different thickness of phosphor encapsulant 22.
The conventional light emitting diode packaging structure is limited to structure and thus can not effectively evenly disperse the phosphor powder. Therefore, it is necessary to have an enhanced light emitting diode packaging structure to overcome the above problems so as to achieve a better color evenness, a faster fabricating process, and a higher yield.